U.S. patent application number 10/421409 was filed with the patent office on 2003-10-30 for method for anticipating problems with electrical wiring.
This patent application is currently assigned to U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration. Invention is credited to Cramer, K. Elliott, Perey, Daniel F., Yost, William T..
Application Number | 20030200786 10/421409 |
Document ID | / |
Family ID | 29254662 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030200786 |
Kind Code |
A1 |
Yost, William T. ; et
al. |
October 30, 2003 |
Method for anticipating problems with electrical wiring
Abstract
Passive and active methods for anticipating problems with
electrical wiring are provided. An insulative material in contact
with an electrical conductor has at least one impurity that is
impregnated in the insulative material and/or disposed thereon. An
environment around the electrical conductor is monitored for the
presence or the level of the impurity(ies) emanating from the
insulative material in the form of a gaseous effluent. An alarm
signal is generated when a predetermined level of the gaseous
effluent is detected.
Inventors: |
Yost, William T.; (Newport
News, VA) ; Cramer, K. Elliott; (Newport News,
VA) ; Perey, Daniel F.; (Yorktown, VA) |
Correspondence
Address: |
NATIONAL AERONAUTICS AND SPACE ADMINISTR
ATION LANGLEY RESEARCH CENTER
3 LANGLEY BOULEVARD
MAIL STOP 212
HAMPTON
VA
236812199
|
Assignee: |
U.S.A. as represented by the
Administrator of the National Aeronautics and Space
Administration
|
Family ID: |
29254662 |
Appl. No.: |
10/421409 |
Filed: |
April 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60376364 |
Apr 24, 2002 |
|
|
|
Current U.S.
Class: |
73/23.2 ;
95/25 |
Current CPC
Class: |
G01N 1/26 20130101; G01N
2030/025 20130101; G01N 33/0063 20130101 |
Class at
Publication: |
73/23.2 ;
95/25 |
International
Class: |
G01N 007/00 |
Goverment Interests
[0002] The invention described herein was made by employees of the
United States Government and may be manufactured and used by or for
the Government for governmental purposes without the payment of any
royalties thereon or therefor.
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A method for anticipating problems with electrical wiring,
comprising steps for: providing an electrical conductor having an
insulative material in contact therewith that (i) provides
electrical insulation properties, and (ii) has at least one
impurity that is at least one of impregnated in said insulative
material and disposed on said insulative material; monitoring an
environment around said electrical conductor for said at least one
impurity emanating from said insulative material in the form of a
gaseous effluent; and generating an alarm signal when a
predetermined level of said gaseous effluent is detected.
2. A method according to claim 1 wherein said step for monitoring
uses at least one technique selected from the group consisting of
optical techniques, gas chromatography techniques, colorimetry
techniques, electromagnetic detection techniques, and ultrasonic
techniques.
3. A method according to claim 1 wherein said alarm signal is
generated once a detected amount of said gaseous effluent decreases
to said predetermined level.
4. A method according to claim 1 wherein said alarm signal is
generated once a detected amount of said gaseous effluent increases
to said predetermined level.
5. A method according to claim 1 further comprising a step for
directing energy to an area of said electrical conductor, said
energy being sufficient to cause emanation of said gaseous
effluent.
6. A method according to claim 5 wherein said energy is heat
energy.
7. A method for anticipating problems with electrical wiring,
comprising steps for: providing a plurality of electrical
conductors, each of said plurality of electrical conductors having
an insulative material in contact therewith that (i) provides
electrical insulation properties, and (ii) has a correspondingly
unique impurity that is at least one of impregnated in said
insulative material and disposed on said insulative material;
monitoring an environment around said plurality of electrical
conductors for each said unique impurity emanating from each said
insulative material in the form of a correspondingly unique gaseous
effluent; and generating an alarm signal when a predetermined level
is detected for any said unique gaseous effluent.
8. A method according to claim 7 wherein said step for monitoring
uses at least one technique selected from the group consisting of
optical techniques, gas chromatography techniques, colorimetry
techniques, electromagnetic detection techniques, and ultrasonic
techniques.
9. A method according to claim 7 wherein said alarm signal is
generated once a detected amount of any said gaseous effluent
decreases to said predetermined level correspondingly associated
therewith.
10. A method according to claim 7 wherein said alarm signal is
generated once a detected amount of any said gaseous effluent
increases to said predetermined level correspondingly associated
therewith.
11. A method according to claim 7 further comprising a step for
directing energy to an area of at least one of said plurality of
electrical conductors, said energy being sufficient to cause
emanation of the gaseous effluent associated with said at least one
of said plurality of electrical conductors.
12. A method according to claim 11 wherein said energy is heat
energy.
13. A system for anticipating problems with an electrical
conductor, the electrical conductor having an insulative material
in contact therewith that (i) provides electrical insulation
properties, and (ii) has at least one impurity that is at least one
of impregnated in said insulative material and disposed on said
insulative material, said system comprising: means for monitoring
an environment around said electrical conductor for said at least
one impurity emanating from said insulative material in the form of
a gaseous effluent; and means for generating an alarm signal when a
predetermined level of said gaseous effluent is detected.
14. A system as in claim 13 further comprising means for directing
energy to an area of said electrical conductor, said energy being
sufficient to cause emanation of said gaseous effluent.
15. A system as in claim 14 wherein said energy is heat energy.
16. A system for anticipating problems with a plurality of
electrical conductors, each of said plurality of electrical
conductors having an insulative material in contact therewith that
(i) provides electrical insulation properties, and (ii) has a
correspondingly unique impurity that is at least one of impregnated
in said insulative material and disposed on said insulative
material, said system comprising: means for monitoring an
environment around said plurality of electrical conductors for each
said unique impurity emanating from each said insulative material
in the form of a correspondingly unique gaseous effluent; and means
for generating an alarm signal when a predetermined level of any
said unique gaseous effluent is detected.
17. A system as in claim 16 further comprising means for directing
energy to an area of at least one of said plurality of electrical
conductors, said energy being sufficient to cause emanation of the
gaseous effluent correspondingly associated with said at least one
of said plurality of electrical conductors.
18. A system as in claim 17 wherein said energy is heat energy.
19. A system as in claim 16 wherein said means for monitoring
comprises a plurality of sensors distributed along said plurality
of electrical conductors.
20. A system as in claim 19 wherein each of said plurality of
sensors is a gas sensor.
Description
CLAIM OF BENEFIT OF PROVISIONAL APPLICATION
[0001] Pursuant to 35 U.S.C. .sctn. 119, the benefit of priority
from provisional application U.S. Serial No. 60/376,364, with a
filing date of Apr. 24, 2002, is claimed for this non-provisional
application.
CROSS-REFERENCE TO RELATED APPLICATION
[0003] This patent application is co-pending with one related
patent application entitled "Marking Electrical Wiring With
Condition Indicators," filed Apr. 21, 2003, and owned by the same
assignee as this patent application (NASA Case No. LAR
16576-1).
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates to assessment of an electrical
conductor or wire. More specifically, the invention is a method for
anticipating problems with electrical wiring by monitoring gaseous
effluence of one or more impurities emitted from the insulation in
contact with an electrical conductor.
[0006] 2. Description of the Related Art
[0007] Wiring (e.g., individual conductors, bundles of conductors,
conductive runs on printed circuit boards, etc.) is used
extensively for the delivery of electrical power and electrically
coded information. Although wiring is typically presumed to be
stable and avoid degradation, the reality is that many applications
are critically affected by aging of electrical insulation disposed
about an electrical conductor. For example, insulation may be
adversely affected by moisture and heat. As the insulation ages,
the loss-tangent of the material changes thereby changing the
frequency response and power loss of the associated electrical
conductors. In power transmission applications, electrical
insulation plays a key role in the prevention of shorts and arcs.
Specifically, insulation degradation can cause functional failures
such as frequency attenuation and short circuits. Such failures may
lead to problems ranging from annoying brief interruptions of
service to lengthy catastrophic system failures.
SUMMARY OF THE INVENTION
[0008] In accordance with the present invention, a method for
anticipating problems with electrical wiring is provided. On its
most basic level, the electrical wiring involves an electrical
conductor having an insulative material in contact therewith. The
insulative material (i) provides electrical insulation properties,
and (ii) has at least one impurity that is impregnated in the
insulative material and/or disposed on the insulative material. The
present invention monitors an environment around the electrical
conductor for presence of the impurity(ies) emanating from the
insulative material in the form of a gaseous effluent. An alarm
signal is generated when a predetermined level of the gaseous
effluent is detected. The method can be extended to a plurality of
electrical conductors where the insulative material associated with
each conductor has a unique impurity associated therewith.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic view of a system for passively
assessing the insulative material of electrical wiring in
accordance with the present invention;
[0010] FIG. 2 is a schematic view of a system for actively
assessing the insulative material of electrical wiring in
accordance with the present invention;
[0011] FIG. 3 is a schematic view of a system for passively
assessing the insulative material of a plurality of electrical
conductors in accordance with the present invention;
[0012] FIG. 4 is a schematic view of a system for actively
assessing the insulative material of a plurality of electrical
conductors in accordance with the present invention; and
[0013] FIG. 5 is a schematic view of another embodiment of a system
for passively assessing the insulative material of electrical
wiring in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring now to the drawings, and more particularly to FIG.
1, one embodiment of a system for assessing electrical wiring in
accordance with the present invention is shown and referenced
generally by numeral 100. More specifically, system 100 anticipates
problems with the insulative material of electrical wiring. Such
wiring is represented in FIG. 1 by an electrical conductor 10 that
has an electrically insulative material 12 in contact therewith.
For each embodiment described herein, it is to be understood that
the conductor 10 is representative of both a standard electrically
conductive wire and an electrically conductive run (on a printed
circuit board (PCB)) where the insulation and the PCB material,
respectively, serve as insulative material 12.
[0015] Insulative material 12 is any material that possesses
electrical insulation properties, a variety of which are well known
in the art. During normal processing of insulative material 12, one
or more impurities 14 molecularly bond to material 12 without
affecting the electrical or structural integrity of material 12.
Such bonding can occur within or throughout the insulative material
12 or on the surface of insulative material 12. For example, if
material 12 were dyed during the processing thereof, impurities 14
would be in the form of the dye(s) that impregnated insulative
material 12. In another example, if insulative material 12 were
printed upon during the processing thereof, the printing ink would
form impurities 14 on the surface of insulative material 12. In
either case, the present invention takes advantage of the fact that
the molecular bonding or attachment energy coupling impurities 14
to insulative material 12 is generally relatively weak.
[0016] During the normal useful life of conductor 10, electric
current will pass therethrough thereby causing a certain low level
of heat to be generated in conductor 12. Over time, the low levels
of heat tend to cause the conductor's insulative material to
degrade. Additionally, greater levels of heat are generated in
conductor 10 if there has been damage thereto. Such damage could be
caused by various forms of mechanical stresses (e.g., bending,
cuts, chafing, etc.), environmental stresses (e.g., high
temperatures, excessive moisture, etc.), or operational stresses
(e.g., current surges, over-voltage conditions, etc.). It has been
discovered that both high and low levels of heat energy can break
the relatively weak molecular bond that couples impurities 14 to
insulative material 12. When these bonds break, impurities 14
escape or emanate from insulative material 12 in a gaseous effluent
form, designated in FIG. 1 by reference numeral 14A.
[0017] At normal operating loads where the heat experienced by
conductor 10 is relatively low, gaseous effluent 14A tends to
emanate from insulative material 12 slowly and at a fairly steady
rate. However, if conductor 10 has undergone some form of
mechanical, environmental, or operational stress, or any
combination thereof, that causes a greater amount of heat to be
generated in the conductor, the rate of escape of gaseous effluent
14A can be substantially greater than the rate experienced at
normal operating currents. By monitoring the presence and/or levels
of gaseous effluent 14A, the present invention provides a method
and system for anticipating problems with conductor 10.
[0018] For example, the system could continually monitor for
gaseous effluent 14A and generate an alarm when one of the
following events occurs:
[0019] (i) the levels of gaseous effluent 14A increase to some
predetermined level that indicates the occurrence of a stressful
event; or
[0020] (ii) the levels of gaseous effluent 14A decrease to some
predetermined level that indicates the possible onset of
degradation of the insulative material because a reduced level of
gaseous effluent 14A normally occurs when the level of impurities
in the insulative material 14 becomes substantially or completely
depleted. Such reduced or non-existent levels of gaseous effluent
14A could signify that a number of stressful events had already
occurred. Thus, another approach of the present invention would
involve monitoring the presence of gaseous effluent 14A, where the
presence of gaseous effluent 14A is indicative of viable insulative
material 12 while the absence of gaseous effluent 14A is indicative
of degraded insulative material 12.
[0021] To achieve the above-described methodology, system 100
includes one or more sensors 102 positioned along and in the
vicinity of conductor 10. Each of sensors 102 is capable of
monitoring a local environment for gaseous effluent 14A. Sensor
outputs are supplied to a processing unit 104 that is programmed
with one or more predetermined levels for comparison with the
levels of gaseous effluent 14A monitored by sensors 102. As
mentioned above, a low predetermined level (meaning levels of
impurities 14 are greatly diminished) could be used to signify the
normal aging of conductors 10 while a high predetermined level
could be used to signify the occurrence of a stressful event. In
either case, once gaseous effluent 14A attains one of the
predetermined levels, processing unit 104 sends an alarm signal to
an alarm unit 106 which can be realized by one or more audio and/or
visual alarm devices. The particular sensor 102 that detects a high
or low level of gaseous effluent 14A also provides a general
location of the anticipated wiring problem so that the conductor 10
can be repaired or replaced.
[0022] Monitoring of gaseous effluent 14A by sensors 102 in each of
the embodiments described herein can be accomplished in a variety
of ways. Accordingly, it is to be understood that each of sensors
102 is representative of a variety of well known systems or
techniques used to monitor levels of gaseous substances such as
gaseous effluent 14A. Such systems and techniques include, but are
not limited to, optical systems and techniques that detect a unique
absorption at specific wavelengths of the electromagnetic spectrum;
gas chromatography systems and techniques that segregate effluents
by size and/or mass and determine the amount of segregated
effluents; colorimetry systems and techniques; electromagnetic
detection systems and techniques, such as optical fiber systems or
other spectrophotometric techniques; and ultrasonic systems and
techniques that monitor changes in scattering, absorption, wave
propagation speed change, and non-linear effects that depend on
changes in the ratio of gaseous specific heats.
[0023] The present method and system can also be used in a "spot
check" fashion as illustrated by the embodiment depicted in FIG. 2
where like reference numerals are used for those elements in common
with the embodiment of FIG. 1. More specifically, a system 200
comprises an energy source 108 capable of directing energy (e.g.,
heat energy) toward an area of interest (between dashed lines 20)
of conductor 10 and its surrounding insulative material 12. The
energy generated and directed by energy source 108 should be
sufficient to cause the emanation of impurities 14 as gaseous
effluent 14A. System 200 can be used in a variety of ways depending
on the bonding or attachment energy associated with impurities 14.
For example, if the bonding energy associated with impurities 14 is
very weak, system 200 can be used to confirm whether or not any of
impurities 14 remain in or on insulative material 12 in area 20.
That is, if a low (or no) level of gaseous effluent 14A is
detected, this condition may indicate that insulative material 12
may not have much useful life left. If, however, the bonding energy
associated with impurities 14 is stronger such that only stressful
situations cause emanation from insulative material 12 as gaseous
effluent 14A, system 200 can be used to determine whether area 20
has experienced such stressful situations. That is, if energy
source 108 can cause emanation of gaseous effluent 14A, it may be
presumed that area 20 has already experienced stress and should be
repaired. The monitoring aspect of system 200 operates in the same
fashion under each of the above situations. Specifically, energy
source 108 directs its energy toward area 20 and sensor 102,
processing unit 104, and alarm unit 106 function as described
earlier for the embodiment of FIG. 1.
[0024] The present invention is not limited to use with a single
conductor and can be extended for use with a plurality of
conductors. By way of illustrative example, two conductors 10 and
11 are shown in FIG. 3, although more than two conductors can also
be monitored. As in the previous embodiments, each of conductors 10
and 11 has insulative material 12 in contact therewith. However,
impurity 14 is associated with conductor 10 while a different
impurity 15 is associated with conductor 11. Accordingly, each
gaseous effluent 14A and 15A is a unique substance and each of
sensors 102 in system 300 is sensitive to and can distinguish
between each gaseous effluent 14A and 15A. Note that each of
sensors 102 is representative of a single gas discriminating
sensing system or multiple dedicated sensing systems. The
processing unit 104 and alarm unit 106 of system 300 function as
previously described in the embodiment of FIG. 1 for each of
gaseous effluent 14A and 15A.
[0025] The present method and system can also be used to "spot
check" one or more conductors in a multiple conductor situation as
illustrated by system 400 of FIG. 4. Once again, like reference
numerals are used for those elements in common with the previous
embodiments. Similar to the system 200, system 400 includes an
energy source 108 used to cause a specific one or all of gaseous
effluents 14A and 15A to emanate from insulative material 12 in
area 20. Sensors 102, processing unit 104 and alarm unit 106
function as previously described for the embodiments of FIGS. 1 and
2 to provide condition indications of one or all of conductors 10
and 11.
[0026] The present invention has thus far been described for a
single impurity associated with each conductor. However, the
present invention could also be used where more than one type of
impurity is associated with a conductor. For example, as
illustrated in FIG. 5 for single conductor 10, insulative material
12 could have both impurities 14 and 15 impregnated therein or
disposed thereon. For example, impurity 14 could be impregnated
(e.g., a dye) while impurity 15 could be disposed on the surface
(e.g., printed) of insulative material 12. If surface impurity 15
is released as a gaseous effluent during normal operating
conditions while impregnated impurity 14 were released only during
stressful operating conditions, system 500 could anticipate both
normal degradation and damage caused by stressful conditions.
[0027] Each of the above-described embodiments could be
intentionally designed to make specific situations of interest
quickly recognizable. That is, rather than being limited by the
impurities inherent in currently manufactured insulative materials,
specific markers could be added to either the insulative material
or directly on an electrical conductor. For example, the insulative
material (e.g., wire coatings, PCBs on which conductive runs are
deposited, etc.) could be intentionally and specifically marked
with one or more "markers" that do not affect electrical and/or
structural integrity of the insulative material. Each such marker
would be selected such that it would emanate into a surrounding
atmospheric environment as a gaseous effluent and in a known
fashion when specific conditions of interest are experienced.
Different markers could be used to indicate each of mechanical
stresses, specific types of environmental or operational stresses,
and normal use degradation. The markers could be disposed in or
layered on the surface of the insulative material or even directly
on the electrical conductor. Additionally or alternatively, the
markers could be impregnated in the insulative material.
[0028] The passive and active systems and methods presented herein
provide the means to anticipate electrical wiring problems before
they occur. In this way, wiring repairs can be affected before
overall system failure. The present invention further provides for
the marking of electrical wiring with specific condition
indicators. As a result, the present invention provides not only
for the anticipation of electrical wiring problems, but also for
the diagnosis of these problems so that both symptoms and their
root causes can be analyzed and addressed.
[0029] Although only a few exemplary embodiments of this invention
have been described in detail above, those skilled in the art will
readily appreciate that many modifications are possible in the
exemplary embodiments without materially departing from the novel
teachings and advantages of this invention. Accordingly, all such
modifications are intended to be included within the scope of this
invention as defined in the following claims. In the claims,
means-plus-function and step-plus-function clauses are intended to
cover the structures or acts described herein as performing the
recited function and not only structural equivalents, but also
equivalent structures. Thus, although a nail and a screw may not be
structural equivalents in that a nail employs a cylindrical surface
to secure wooden parts together, whereas a screw employs a helical
surface, in the environment of fastening wooden parts, a nail and a
screw may be equivalent structures.
* * * * *